A cerebral aneurysm (i.e., an acute subarachnoid hemorrhage) is a cerebrovascular swelling on the wall of an artery that develops because of a congenitally weak cerebral artery or due to arteriosclerosis, a bacterial infection, a head wound, brain syphilis, etc. The cerebral aneurysm may develop suddenly without initial symptoms and can cause extreme pain. In general, in 15% of cerebral aneurysm cases, the patient dies suddenly upon development of the cerebral aneurysm. In another 15% of cerebral aneurysm cases, the patient dies under medical treatment and, in 30% of cerebral aneurysm cases, the patient survives after treatment but feels an acute aftereffect. As such, a cerebral aneurysm is a very concerning development.
A cerebral aneurysm may be treated through either an invasive therapy or a non-invasive therapy. Of these, the non-invasive therapy typically fills the cerebral aneurysm with a micro-coil. Generally, filling the cerebral aneurysm with the micro-coil causes blood to clot, prevents an additional inflow of blood, and decreases the risk of a ruptured aneurysm (i.e., an embolization). Advantageously, the non-invasive therapy can ease the aftereffects of brain surgery and can shorten hospitalization time.
The system used in non-invasive therapy typically includes a micro-coil and a delivery pusher for carrying the micro-coil to the patient's cerebral aneurysm. When the micro-coil is properly placed in or near the cerebral aneurysm, an operator (e.g., a physician) separates the micro-coil from the delivery pusher. To initiate detachment of the coil, current micro-coil systems generally require a power supply (for thermal or electrolytic detachment) or a mechanical detachment handle that is attached to the proximal end of the delivery pusher after the coil is positioned in the aneurysm.
Certain mechanical detachment systems employ the use of a wire to retract an element that holds some component of the coil. Certain other mechanical detachment systems use interlocking arms that disengage when advanced beyond a micro-catheter tip, or a ball-screw mechanism that unscrews the coil from a tip of the delivery pusher when the pusher is rotated, or a hydraulic system that ejects the coil from the delivery pusher tip when pressurized with saline.
However, existing schemes for detaching a micro-coil from a delivery pusher often present an unnecessary risk that the micro-coil will be inadvertently released at an incorrect time (e.g., prior to delivery of the micro-coil to the vascular disorder). This can negatively impact the treatment of the patient.
Accordingly, a need exists for improved devices and methods for delivering an implant, such as an embolic micro-coil, to a vascular disorder of a patient, such as a cerebral aneurysm.